Motor-operated spring-closing circuit breaker

ABSTRACT

A circuit breaker comprises spring closing means and a motor drive structure for charging the spring-closing means with improved means supporting the motor drive structure in a cooperating relationship with the spring closing means.

United States atent Inventor Fred Bould Pittsburgh, Pa.

Appl.' No. 874,648

Filed Nov. 6, 1969 Patented Aug. 17, 1971 Assignee Westinghouse ElectricCorporation Pittsburgh, Pa.

MOTOR-OPERATED SPRING-CLOSING CIRCUIT BREAKER 5 Claims, 4 Drawing Figs.

US. Cl 200/153, 200/50 Int. Cl 01h 3/00 Field 01 Search 335/68, 76;

ZOO/153.23, 153; 74/2, 575

References Cited UNITED STATES PATENTS 6/1953 Lingal et a1. 74/2 X6/1960 Hay 200/153X 5/1965 Frink etal.. 200/153X 5/1966 Fischer 200/153Primary Examiner--Miiton O. Hirshfieid Assistant Examiner-Ulysses WeldonAlt0rney.\'A. T. Stratton, C. L. McHale and W. A. Elchik ABSTRACT: Acircuit breaker comprises spring closing means'and a motor drivestructure for charging the springclosing means with improved meanssupporting the motor drive structure in a cooperating relationship withthe spring closing means PATENTED AUG I 71971 SHEET 2 OF 3 PATENIEU AUG1.7 mil SHEET 3 BF 3 MOTOR-OPERATED SPRING-CLOSING CIRCUIT BREAKERCROSS-REFERENCES TO RELATED APPLICATIONS The applications of Fred Bouldet al., Ser. No. 770,296 filed Oct. 24, 1968, and of Fred Bould, Ser.No. 836,313 filed June 25, 1969 are related to the present applicationin a manner that will be hereinafter set forth under the description ofthe priorart.

BACKGROUND OF THE INVENTION 1. Field of the Invention Motor-operatedspring-closing circuit breaker.

2. Description of the Prior Art In the above-mentioned application ofFred Bould et al., Ser. No. 770,296, ,there is disclosed aspring-closing mechanism for closing a circuit breaker, with manualmeans for charging the spring-closing mechanism. In the above-mentionedapplication of Fred Bould, Ser. No. 836,313 there is disclosed amotor-operated spring-closing circuit breaker. The present invention isan improvement over both of the abovementioned applications in that thepresent invention provides an improved motor-operated spring-closingcircuit breaker with-improved means supporting the motor drive structurein a cooperating relationship with the spring-closing means. Theimproved supporting or mounting means provides a precise location of themotor roller arm preventing undesirable deflections of the roller armunder load conditions and keeping the loads on the motor housing withinsafe limits. The mounting is such as to facilitate assembly and removalof the motor drive structure and a standard drill-type motor body can beutilized in the combination.

SUMMARY OF THE INVENTION A circuit breaker comprises spring-closingmeans and a motor drive structure for charging the spring-closing means,with improved means supporting the motor drive structure for operatingthe spring-closing means. The circuit breaker comprises a metallichousing structure comprising a baseplate and a pair of spaced generallyparallel sideplates connected to the baseplate with a pair of spacedgenerally parallel center plates connected to the base plate within thewidthwise dimension of the sideplates. The center plates support acrankshaft that is rotatable about an axis to charge a pair of closingsprings, and a ratchet is connected to the crankshaft. The sideplatesand center plates support a jackshaft that is movable to operate themovable contacts of the breaker. A reciprocating pawl structure issupported to advance the ratchet to thereby charge the closing springs.The motor drive structure comprises a main body motor part and arotatable output shaft structure extending from and supported on themain body motor part. The main body motor part is supported on one ofthe breaker sideplates and the nose or end part of the output shaftstructure is supported on a bearing support that is supported on one ofthe center plates. Upon energization of the motor and rotation of theoutput shaft structure, a cam part or roller arm on the output shaftstructure between the nose and the main body motor part rotates andoperates against the reciprocating pawl structure to advance the ratchetwheel to thereby charge the closing springs. By supporting both the mainbody part and the end part of the motor drive structure, the roller armis maintained in the operative position under operating loads and theloads on the body of the motor are kept within safe limits. A standarddrill-type motor, including an aluminum motor housing, can be utilizedin the combination. The motor drive structure is readily assembled inavailable space between one of the sideplates and one of the centerplates of the breaker support structure.

FIG. 1 is an end view, with parts broken away and with certain partsleft out for the purpose of clarity, of a circuit breaker constructed inaccordance with principles of this invention;

FIG. 2 is a sectional view taken generally along the line II-II of FIG.1;

FIG. 3 is a partial sectional view taken generally along the lineIII-III of FIG. 1 with the crankshaft and closing spring being shown inside elevation; and

FIG. 4 is a partial sectional view, with parts broken away and withparts left out for the purpose of clarity, looking down on the motordrive structure and reciprocating pawl structure to illustrate thesupport of the motor drive structure on the one center plate and onesideplate.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, thereis shown in FIGS. 1 and 2 a three-pole circuit breaker 5 comprising asupport structure or housing structure 7 and a circuit breaker structure9 supported on the housing structure 7. The housing structure 7comprises a metallic baseplate 11, a pair of spaced metallic side plates13 fixedly secured to flanges of the base plate 1 1, a pair of metalliccenter plates 17 fixedly mounted on the base plate 11 and a backwallstructure indicated generally at 19.

The circuit breaker structure 9 is a three-pole structure comprising astationary contact 21 (FIG. 2) and a movable contact 23 for each poleunit. Each of the movable contacts 23 is supported on a conductingcontact arm 25 that is pivotally supported on a terminal conductor 27 bymeans of a pivotal support means 29. In each pole unit, a separateinsulating connecting member 31 is pivotally connected at one endthereof to the contact arm 25 and at the other end thereof to a lever 33that is welded to a common jackshaft 35 that extends across all of thepoles of the circuit breaker. There is a separate lever 33 for each poleunit welded to the common jackshaft 35. Only one of the contactstructures is shown in FIG. 1. The contact structures for the centerpole and for the left-hand (FIG. 1) pole are left out of the drawing inFIG. 1 merely for the purpose of clarity. It can be understood that thecontact structures for all three-pole units are the same as the onecontact structure shown in FIGS. 1 and 2.

The jackshaft 35 is supported for pivotal movement, about the elongatedaxis thereof, on the sideplates 13 and center plates 17. The connectingmember 31, levers 33 and jackshaft 35 are part of a stored-energyspring-closing mechanism 39 that is operable to close the contacts 23,21. The mechanism 39 comprises a link 41 that is pivotally connected, atone end thereof, to the lever 33 of the center pole by means of a pin43. The link 41 is pivotally connected at the other end thereof, to alink 45 by means of a knee pivot pin 47. A roller member 49, that servesas a cam follower, is mounted on the pin 47 to cooperate with a closingcam 51. The link 45 is pivotally connected at the other end thereof to alatch member 53 by means of a pin 55. The latch member 53 is mounted forpivotal movement about a fixed pivot pin 57 that is supported on theleft-hand (FIG. 1) center plate 17. A tension spring 59 is connected tothe pin 55 to reset the linkage following a tripping operation of thecircuit breaker. The latch member 53 engages the periphery of a tripshaft 63 in proximity to a cutout portion of the shaft 63, which cutoutportion is provided so that when the trip shaft 63 is rotated in acounterclockwise direction the latch member 53 will be free to move inthe cutout portion to the tripped position. The trip shaft 63 issupported for pivotal movement about the elongated axis thereof betweenone of the center plates 17 and one of the sideplates 13.

A roller latch 67 (FIG. 2) is rotatably supported on and between thetwin plates of the closing cam 51. The closing cam 51 is fixedly securedto a crankshaft 71 that is rotatably supported on suitable bearings thatare secured to the center plates 17. A pair of crank arms 73 are fixedlymounted on the crankshaft 71 at the opposite ends of the crankshaft 71.A ratchet member 75 is fixedly mounted on the crankshaft 71. Areciprocating pawl structure 78 (FIGS. 1 and 3) is supported on thecrankshaft 71 for pivotal reciprocating movement relative to thecrankshaft 71 to cooperate with the ratchet 75. A separate tensionspring 79 is operatively connected at the end of each of the crank arms73 by means of a pivot pin 80. Each of the springs 79 is connected to aspring support 81 that is pivotally connected to the associated arm 73by means of the associated pivot pin 80. Each of the tension springs 79is connected, at the other end thereof, to a rod 82 that is secured tothe center plate 17. A manual operating mechanism, indicated generallyat 83 (FIG. 1), is provided for manually charging the closing springs79. A latch member 85 (FIG. 2) is pivotally mounted on a pin 87 andbiased in a clockwise (FIG. 2) direction to the latching positionwherein the latch 85 engages the roller 67 to latch the closing cam 51and crank shaft 71 to prevent counterclockwise movement of the closingcam 51 and crank shaft 71.

The circuit breaker is shown in FIG. 2 in the contact open position withthe stored energy closing springs 79 in the charged condition. As isshown in FIG. 2, the spring support pins 80 of the tension springs 79are below a line between the center of the spring support rod 82 and thecenter or axis of the crank or shaft 71 so that the charged tensionsprings 79 are operating to bias the crankshaft 71 in a counterclockwisedirection. Counterclockwise movement of the crankshaft 71 is preventedby the engagement of the latch member 85 with the latch roller 67 thatis mounted on the closing cam 51. The latch member 85 is operated to theunlatching position to close the circuit breaker in a manner describedin the abovementioned application of Fred Bould et al., Ser. No.770,296. When it is desired to close the breaker, the latch 85 ispivoted in a counterclockwise (FIG. 2) direction to thereby release theroller 67. When the roller 67 is released, the closing cam 51 and thecrank shaft 71 are free to rotate in a counterclockwise direction, andthe closing springs 79, operating on the crank arms 73, operate torotate the crank shaft 71 in a counterclockwise direction as the springs79 discharge. During this movement, the closing cam 51 will force theroller 49, and the link 41, to the closed position. During this closingmovement ofthe link 41, of the lever 33 (FIG. 2) of the center pole unitis forced in a counterclockwise direction to rotate the jackshaft e5counterclockwise to simultaneously move the three contact arms 25 in aclockwise direction about the pivots 29 to the closed position. In theclosed position, the engagement of the closing cam 51 with the roller 49serves to prop the link member 41 in the closed position to therebymaintain the jackshaft 35 and contacts 23 in the closed position.

With the contacts in the closed position and the closing springdischarged, the circuit breaker may be automatically tripped open, inresponse to an overload above a predetermined value in any of the poleunits, by operation of the trip shaft 63 in a manner described in thepatent application of Nagar J. Patel, Ser. No. 770,236, filed Oct. 24,1968. During the tripping operation, the trip shaft 63 is rotated in acounterclockwise (FIG. 2) direction. When the trip shaft 63 is rotatedcounterclockwise, the trip shaft moves to permit the latch member 53 tomove in the cutout portion of the trip shaft 63 thereby permitting thelatch member 53 to move in a counterclockwise direction about the pivot57 to the tripped position. The compressed contact springs 93 (FIG. 2)and an opening spring 99 (FIG. 1) then operate to move the contact arms25 toward the open position which movement occurs because the pivot 55is free to move so that the link 45 can move to the tripped positionwith the toggle 45, 41 collapsing to permit the lever 33 and jack shaft35 to move in a clockwise direction to the tripped open position. Thus,movement of the trip shaft 63 to the tripped position permits themembers 41, 45, 53 to move to the tripped position wherein the roller 49and link 41 no longer restrain the lever 33 in the closed position, andthe springs 93, 99 operate to move the jackshaft 35 and the threecontact arms 25 to the tripped open position.

With the circuit breaker in the tripped open position, the breaker isreset and the closing springs 79 are charged by operation of themotordrive structure 101 in a manner to be hereinafter more specificallydescribed. In order to reset the circuit breaker and charge the closingsprings 79, the crankshaft 71 is rotated through an angle of more than180 of the spring charged operating position seen in FIG. 2. As thecrankshaft 71 moves to the position seen in FIG. 2, the roller 49 ridesoff of the peak of the cam 51 into the depression seen in FIG. 2. Whenthe roller 49 is free to move into the depression of thecam 51, thespring 59 (FIG. I) biases the latch 53 clockwise (FIG. 2) to move thelatch 53 to the reset position pulling links 45, 41 and the roller 49 tothe reset position wherein the roller 49 is positioned in the depressionof the cam 51 (FIG. 2). When the latch 53 moves out of the notch of thetrip shaft 63, suitable spring meansoperates to rotate the trip shaft 63clockwise to the latching position wherein the periphery of the tripshaft 63 again latches the latch member 53 to latch the parts in thereset position seen in FIG. 2. As the crankshaft 71 moves more than I80to the position seen in FIG. 2, the springs 79, which are movedovercenter, take over to bias the crankshaft 71 in a counterclockwise(FIG. 2) direction, and the roller 67 engages the latch to latch thecrankshaft 71 in the charged position seen in FIG. 2, and the circuitbreaker is prepared for another closing operation.

When the circuit breaker is in the contact closed position with thestored energy closing springs 97 discharged the spring closed means isoperated to the charged position by operation of the motor drivestructure 101 (FIGS. 1, 3 and 4) to rotate the crankshaft 71 through anangle of slightly more than 180 (approximately 184) to charge thesprings 79 during which movement the roller 49 rides on a fixed radiusof the cam 51 to a position just short of the peak of the cam surface ofthe cam member 51. This charging movement of the cam 51 is morespecifically described in the above-mentioned application Ser. No.770,296.

With the parts in the contact closed spring charged position, thefollowing sequence of operations can occur.

Upon the occurrence of an overload above a predetermined value, the tripmeans indicated generally at (FIG. 1) is automatically operated torotate the trip shaft 63 to release the latch member 53 and permit thetoggle 41, 45 to effect an opening operation in the same manner as washereinbefore described. With the toggle 41, 45 collapsed, the spring 59operates to draw the roller 49 into the depression of the cam 51resetting the linkages 53, 41, 45 and the trip shaft 63 is moved byspring means into the latching reset position seen in FIG. 2. The partsat the end of this tripping operation will be in the position seen inFIG. 2 wherein the mechanism is reset and relatched, and wherein theroller member 49 is in the depression of the cam 51 so that the partsare prepared for a closing operation. When the closing springs 79 arecharged an operator can immediately operate the closing latch 85 (FIG.2) to release the roller 67 whereupon the circuit breaker is operated tothe closed position in the same manner as was hereinbefore described.With the parts in the closed position, if an overload above thepredetermined value occurs the trip mans 95 will be automaticallyoperated to rotate the trip shaft 63 to the tripped position to effect atripping operation in the same manner as mentioned before described.With the parts in the tripped position and the closing springs 79discharged, another charging operation of the closing springs 79 will berequired in order to provide another closing operation. Thus, when thecircuit breaker is in the contact closed spring charged position, thecircuit breaker can be tripped and then closed and then tripped again inrapid sequence.

The reciprocating pawl structure 78 (FIG. 3) comprises a reciprocatingmember 105 that comprises a pair of spaced twin plates, that straddlethe ratchet wheel 75, and a bight portion 107 connecting the twinplates. The reciprocating member 105 is mounted on the crank shaft 71for movement relative to the crank shaft 71 about the axis of the crankshaft 71. A driving pawl 109 is pivotally mounted on the reciprocatingmember 105 between the twin plates of the member 105 by means of a pin 1l3, and a torsion spring 1 biases the pawl 109 in a counterclockwisedirection about the pin 113 into engagement with the ratchet wheel 75. Atension spring member 117 biases the reciprocating member 105 in aclockwise direction about the crankshaft 71. A holding pawl 121 ispivotally mounted on one of the center plates 17 by means of a pin 123and biased in a counterclockwise direction, by means of a torsion spring125, into engagement with the ratchet wheel 75.

The motor drive structure 101 comprises a main body motor part 131 andan output shaft structure 133 supported on the main body motor part 131.The output shaft structure 133 comprises an end part or nose part 135and a roller arm 137 intermediate the end part 135 and the main bodymotor part 131. A roller member 139 is rotatably mounted on a pin 141that is supported on the roller arm 137. The main body motor part 131comprises a motor housing 148 and an electric motor structure supportedwithin the motor housing 148. A standard aluminum housing drill-typemotor has been successfully used in the combination with the back handleof the motor removed and with the two screws 149, that formerly securedback handle of the drill-type motor to the motor housing 148, being usedto secure the motor housing 148 to the one sideplate 13. The screws 149support the motor drive structure 101 on the sideplate 13, and anadditional bearing support 151 is supported on one of the center platesto provide additional support for the end part 135 of the output shaftstructure 133 to prevent undesirable deflection of the output shaftstructure under operating load conditions and to keep the loads on themotor housing within safe limits. With the improved mounting means ofthis invention a standard aluminum housing drill-type motor can beutilized in the combination with the roller arm being positively locatedand with the overall support means keeping the loads on the motorhousing within safe limits.

As can be understood with reference to FIG. 4, the bearing support 151is a roller bearing comprising a race 153 fixedly supported in anopening on the one center plate 17, a journal 155 that receives the endpart 135 of the output shaft structure 133 and a plurality of ballbearings 157 disposed around the journal between the journal and race topermit the journal and endpart 135 to freely rotate relative to the race153 and plate. 17 while supporting the end part 135 against radialmovement.

As can be seen in FIG. 3, the closing springs 79 are in the chargedposition with the closing latch 85 (FIG. 2) engaging the roller 67 ofthe cam 51 to latch the crankshaft 71 release of the latch 85, thesprings 79 discharge rotating the crankshaft 71 approximately 180 toclose the circuit breaker in a manner hereinbefore described. Upondischarge of the closing springs 79 suitable limit switch means isactuated in a well-known manner by the breaker mechanism to energize themotor drive structure 101. Upon energization of the motor drivestructure 101, the output shaft structure 133 is rotated in a clockwise(FIG. 3) direction about the axis thereof. Upon clockwise (FIG. 3)rotation of the output shaft structure 133 the roller arm 137 is rotatedand during each revolution of the output shaft structure 133 the roller139, operating against the bight part 107 of the reciprocating pawlstructure 78 moves the reciprocating pawl structure 78 in acounterclockwise direction during which movement the driving pawl of 109operates against one of the teeth of the ratchet 75 to advance theratchet 75 and crankshaft 71. As the roller arm 137 moves I80 from theposition seen in FIG. 3, the reciprocating pawl structure 78 willadvance the ratchet 75 and crankshaft 71 in a counterclockwisedirection, and as the roller arm 137 moves the remaining 180 of a 360revolution, the spring 117 will return the reciprocating pawl structure78 to the position seen in FIG. 3 with the holding pawl 121 holding theratchet 75 and crankshaft 71 in the advanced position. Thus, as theoutput shaft structure 133 rotates, the ratchet 75 is advanced by thedriving pawl 109 and alternately held by the holding pawl 121 until thecrankshaft 71 moves more than 180 to an overcenter position wherein thecharged closing springs 79 again bias the crankshaft 71 in acounterclockwise direction with the ratchet 75 and crankshaft 71becoming latched from closing movement by the latch member (FIG. 2)which engages the roller 67 on the cam 51 that is fixed to thecrankshaft 71. When the closing springs 79 reach the fully chargedposition, the driving pawl 109 is adjacent a missing tooth portion 154(FIG. 3) of the ratchet 75 so that continued rotation of the motor willnot operate against the teeth of the ratchet 75, and the motor can bebrought to a stopped condition without damaging the parts and withoutputting undue forces on the parts. The motor 101 is automaticallydeenergized by suitable limit switch means in a manner well known in theart.

I claim as my invention:

1. A circuit breaker comprising a support structure, a circuit breakermechanism supported on said support structure, said support structurecomprising a baseplate and a pair of spaced generally parallelsideplates connected to said baseplate, a pair of spaced generallyparallel center plates connected to said baseplate within the dimensionbetween said sideplates and supported in a generally parallelrelationship with respect to said sideplates, said circuit breakermechanism comprising a closing spring means and a motor drive structureoperable to charge said closing spring means, said closing spring meanscomprising a crankshaft supported for rotation on said center plates anda pair of closing springs connected to saidcrankshaft, a ratchet wheelconnected to said crankshaft, a reciprocating pawl structure mounted onsaid crankshaft for movement relative to said crankshaft, said motordrive structure comprising a main body motor part and a rotatable outputshaft structure extending from said main body motor part, said rotatableoutput shaft structure comprising an end part and an intermediate part,said intermediate part being intermediate said end part and said mainbody motor part, support means supporting said motor drive structure onsaid support structure, said support means comprising a first supportand a second support, said first support fixedly supporting said mainbody motor part on one of said sideplates, said second supportcomprising a bearing support supported on one of said center plates andreceiving said end part of said output shaft structure therein, saidbearing support supporting said end part of said output shaft structureagainst radial movement with said end part rotating on said bearingsupport during operation of motor drive structure, and upon energizationof said motor drive structure said output shaft rotating and saidintermediate part operating against said reciprocating pawl structure toadvance said ratchet wheel to thereby rotate said crankshaft to chargesaid closing spring means.

2. A circuit breaker according to claim 1, said intermediate partcomprising an operating arm movable upon rotation of said output shaftthrough a first part of a 360 revolution of said output shaft structureto move said reciprocating pawl structure against a tooth of saidratchet wheel to advance said ratchet wheel, and spring means operatingto return said reciprocating pawl structure to position saidreciprocating pawl structure adjacent another tooth of said ratchetwheel during the second part of said 360 revolution of said output shaftstructure.

3. A circuit breaker according to claim 1, and said intermediate part ofsaid output shaft structure comprising a roller arm part operableagainst said reciprocating pawl structure upon rotation of said outputshaft structure.

4. A circuit breaker according to claim 3, and said second supportcomprising a ball bearing support supporting said end part againstradial movement during operation of said motor drive structure.

5. A circuit breaker according to claim, said circuit breaker being amultipole circuit breaker, said circuit breaker mechanism comprising anelongated jackshaft common to all of the poles of said circuit breaker,each of said poles comprising a stationary contact and a movablecontact, means operatively connecting each of said movable contacts withsaid jackshaft, means supporting said jackshaft on said sideplates andsaid center plates for movement about the elongated axis thereof, aclosing cam on said crankshaft between said center plates, link meansoperatively connecting said closing cam with said jackshaft, said motordrive structure being operable to operate said reciprocating pawlstructure to rotate said crankshaft from a spring discharged position toa spring

1. A circuit breaker comprising a support structure, a circuit breakermechanism supported on said support structure, said support structurecomprising a baseplate and a pair of spaced generally parallelsideplates connected to said baseplate, a pair of spaced generallyparallel center plates connected to said baseplate within the dimensionbetween said sideplates and supported in a generally parallelrelationship with respect to said sideplates, said circuit breakermechanism comprising a closing spring means and a motor drive structureoperable to charge said closing spring means, said closing spring meanscomprising a crankshaft supported for rotation on said center plates anda pair of closing springs connected to said crankshaft, a ratchet wheelconnected to said crankshaft, a reciprocating pawl structure mounted onsaid crankshaft for movement relative to said crankshaft, said motordrive structure comprising a main body motor part and a rotatable outputshaft structure extending from said main body motor part, said rotatableoutput shaft structure comprising an end part and an intermediate part,said intermediate part being intermediate said end part and said mainbody motor part, support means supporting said motor drive structure onsaid support sTructure, said support means comprising a first supportand a second support, said first support fixedly supporting said mainbody motor part on one of said sideplates, said second supportcomprising a bearing support supported on one of said center plates andreceiving said end part of said output shaft structure therein, saidbearing support supporting said end part of said output shaft structureagainst radial movement with said end part rotating on said bearingsupport during operation of motor drive structure, and upon energizationof said motor drive structure said output shaft rotating and saidintermediate part operating against said reciprocating pawl structure toadvance said ratchet wheel to thereby rotate said crankshaft to chargesaid closing spring means.
 2. A circuit breaker according to claim 1,said intermediate part comprising an operating arm movable upon rotationof said output shaft through a first part of a 360* revolution of saidoutput shaft structure to move said reciprocating pawl structure againsta tooth of said ratchet wheel to advance said ratchet wheel, and springmeans operating to return said reciprocating pawl structure to positionsaid reciprocating pawl structure adjacent another tooth of said ratchetwheel during the second part of said 360* revolution of said outputshaft structure.
 3. A circuit breaker according to claim 1, and saidintermediate part of said output shaft structure comprising a roller armpart operable against said reciprocating pawl structure upon rotation ofsaid output shaft structure.
 4. A circuit breaker according to claim 3,and said second support comprising a ball bearing support supportingsaid end part against radial movement during operation of said motordrive structure.
 5. A circuit breaker according to claim, said circuitbreaker being a multipole circuit breaker, said circuit breakermechanism comprising an elongated jackshaft common to all of the polesof said circuit breaker, each of said poles comprising a stationarycontact and a movable contact, means operatively connecting each of saidmovable contacts with said jackshaft, means supporting said jackshaft onsaid sideplates and said center plates for movement about the elongatedaxis thereof, a closing cam on said crankshaft between said centerplates, link means operatively connecting said closing cam with saidjackshaft, said motor drive structure being operable to operate saidreciprocating pawl structure to rotate said crankshaft from a springdischarged position to a spring charged position to charge said closingspring means, latch means for latching said crankshaft in the springcharged position, upon release of said latch means said closing springmeans rotating said crankshaft and said closing cam operating throughsaid link means and said jackshaft to move said movable contacts to theclosed position.